Lessons from ten years of psychotherapy process research

: Our knowledge regarding relevant aspects of psychotherapy is very fragmented; robust and replicated results are still scarce. Only a few variables have been found to consistently predict outcome across most therapies. Only in the field of alliance research it has been possible to perform meta-analyses that clearly demonstrate the impact of this factor on final outcomes. Despite these limitations, psychotherapy process research is a powerful tool for uncovering change mechanisms and is at present widely implemented. Our conclusion is that, in order to generate useful future knowledge, change mechanisms need to be linked to ongoing change; this, in turn, requires models of change, hopefully of a transtheoretical nature.